Extrapolation is a well-known numerical technique for raising the approximation order. Several variants of extrapolation can be used for elliptic partial diierential equations. The basic algorithmic variants are Richardson extrapolation, truncation error extrapolation and extrapolation of the functional. In multi-dimensional problems the error can be expanded into multivariate polynomials with ...

In this paper, first the limitations of the ray-based method and the one-way wave-field extrapolation migration (WEM) in imaging steeply dipping structures are discussed by some examples. Then a new method of the reverse time migration (RTM), used in imaging such complex structures is presented. The proposed method uses a new wave-field extrapolator called the Leapfrog-Rapid Expansion Method (L...

Fredrich Froebel was a scientist, both in instinct and training, his life coincided with an important dynamic period of scientific growth. I take this opportunity to delve into some history futurology examine the heritage legacy work. The usual interpolation is reading data: where there exist consistent trends within broad set data then reader can reasonably infer value intervening points, ‘rea...